1. Field of the Invention
The present invention relates to a variable duct apparatus, in particular, a variable duct apparatus provided between each of a bumper and an upper opening, and a radiator in a vehicle.
2. Description of the Related Art
Generally, a bumper and a front grille arranged on the front side portion of a vehicle are each provided with an opening that admits outside air to the front side of each of a radiator and a cooler condenser installed in an engine room. The outside air admitted from such openings is used to cool the engine coolant in the radiator, and also to cool the cooler condenser. However, there is concern that during high-speed running or the like, running resistance will become greater as the amount of outside air admitted into the engine room from the opening in each of the bumper and the front grille increases, causing a decrease in fuel efficiency. Also, it is feared that the engine will be cooled excessively in winter or cold climate areas. Further, there is concern that in winter or cold climate areas, the warming-up performance of the engine or the catalytic activity of an exhaust gas purifier will be affected.
Accordingly, a technique exists in which a variable duct apparatus is provided in each of these openings, and the amount of outside air to be admitted is regulated by opening and closing the duct in accordance with the vehicle speed, the temperature of the engine coolant, or the engine load state, thereby preventing excessive cooling of the engine and a deterioration in fuel efficiency due to an increase in running resistance caused by an increase in the amount of outside air admitted into the engine room from the opening in the bumper or the front grille.
Japanese Unexamined Patent Application Publication No. 1993-58172 proposes a variable-duct controller which is provided between an opening formed in each of a bumper and a front grille, and a radiator. This variable-duct controller includes a first variable louver provided in the opening formed in the front grille, and a second variable louver provided in the opening formed in the bumper. In accordance with the engine load state, controls of the opening and closing of the first variable louver and the second variable louver are executed independently by separate actuators.
Japanese Unexamined Patent Application Publication No. 2007-320527 proposes a variable duct apparatus that controls a variable louver provided between an opening formed in a bumper and a radiator, and a movable shutter provided between an opening formed in a front grille and the radiator. The variable duct apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2007-320527 mentioned above will be described with reference to FIG. 12.
As illustrated in the drawing, a vehicle 110 includes a bumper 103 in which an air inlet 104 is formed. Above the bumper 103, a front grille 101 in which a grille opening 101a is formed is disposed along the bumper 103. A radiator 106 is arranged opposed to the grille opening 101a and the air inlet 104.
The variable duct apparatus 100 includes a shutter mechanism 102 provided between the grille opening 101a and the radiator 106 and formed by a plurality of flat shutter plates 102a. In the air inlet 104, there are provided baffle plates 105 extending in the vehicle width direction and formed in a wing-like shape that curves while gradually decreasing in thickness toward the vehicle's rearward direction R as viewed in cross-section taken along the front-rear direction of the vehicle indicated by an arrow FR. The shutter plates 102a and the baffle plates 105 are controlled so as to be movable by separate motors in accordance with the outside temperature or the battery's water temperature, thereby executing admission and blocking of outside air to the radiator 106.
According to Japanese Unexamined Patent Application Publication No. 1993-58172 mentioned above, there is concern that since the swing motions of the first variable louver and second variable louver are controlled independently by separate actuators, an increase in manufacturing cost and weight will occur. Also, there is concern that when a vehicle equipped with such a variable duct controller runs on a flooded road, if the opening in the bumper is blocked by the second variable louver, excessive water pressure will be applied to the second variable louver during running of the vehicle, causing damage to the second variable louver. Furthermore, there is concern that when the second variable louver freezes in a cold climate area or the like, engine performance will be affected by the resulting cooling failure or the like.
According to Japanese Unexamined Patent Application Publication No. 2007-320527 mentioned above, there is concern that since actuations of the shutter mechanism 102 and baffle plates 105 are controlled independently by separate actuators, an increase in manufacturing cost and weight will occur as in the case of Japanese Unexamined Patent Application Publication No. 1993-58172. Likewise, there is concern that when the vehicle runs on a flooded road, if the air inlet 104 is blocked by the baffle plates 105, excessive water pressure will be applied to the baffle plates 105 during running of the vehicle, causing damage to the baffle plates 105. Furthermore, there is concern that when the baffle plates 105 freeze in a cold climate area or the like, engine performance will be affected by the resulting cooling failure or the like.